Question

piece of work in 6 hours and 4 hours respectively after the first has worked for 2 hours he he is joined by the other by when should the work be completed

Answer 1

$one \: hour \: work \: of \: a = \frac{1}{6} \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: b = \frac{1}{4} \\ both \: one \: hour \: work = \frac{1}{6} + \frac{1}{4} = \frac{5}{12} \\ 2 \: hr \: work \: of \: a = \frac{2}{6} = \frac{1}{3} \\ remaing \: work = 1 - \frac{1}{3} = \frac{2}{3} \\ no \: of \: hrs \: to \: finish \: work \: by \: both = \frac{ \frac{2}{3} }{ \frac{5}{12} } \\ = \frac{24}{15} = \frac{8}{5} = 1hr \: 36 \: min$